WASHINGTON — Republican Sen. Lamar Alexander faces two tea party-like challengers in the Tennessee GOP primary Thursday. But the “establishment” Republican has not run a campaign to out-right the far right. Instead, he’s actually promoted his record as a dealmaker, working across the aisle to get things done in Congress.

How is it that bipartisanship – Senator Alexander calls it “results” on the campaign trail – can sell in a Southern state with an all-GOP state assembly and governor, a state that has voted Republican in the last four presidential elections?

Alexander touts his conservative values. Alexander’s leading tea party opponent, state Rep. Joe Carr, says that the senator has lost his way over his 12 years in Washington. The senator’s scores with some conservative groups aren’t great: 49 percent from Heritage Action and 60 percent for 2013 from the American Conservative Union.

So Alexander touts his own, custom-made “Tennessee scorecard,” built up over a lifetime of civic service, including two terms as governor: an “A” rating from the National Rifle Association, a 100 percent rating from the National Right to Life Committee, and his 100 percent score from the US Chamber of Commerce.

In ads, he puts his conservative credentials front and center: One ad features actor and former US Sen. Fred Thompson (R) of Tennessee, whose first words are: "Lamar Alexander is a conservative United States senator who deserves reelection." Another attacks Obamacare, a defining conservative issue. A former US secretary of Education, Alexander also ran an ad against "a national school board," that is, too much federal interference in education.

The senator emphasizes results. What really sets off Mr. Carr and his supporters, such as conservative radio host Laura Ingraham, is that Alexander was one of 14 Republicans to vote for comprehensive immigration reform. The bipartisan bill passed the Senate last year but hit a brick wall in the House.

The senator can deflect Carr’s criticism somewhat because he recently voted against President Obama’s request for emergency aid to handle the child-migrant crisis on the border – a fact he slipped into his closing ad of the campaign.

But he’s hung tough over support for immigration reform as a way to fix the overall problem. And he likes to talk about the nine bills he helped become law despite a divided Senate last year, such as a drug-safety law and reform of federal student loans. "Some people just want to make a speech," he said at a recent campaign stop. "I want to get a result."

Jennifer Duffy, who tracks the Senate for the independent Cook Political Report, says this message plays well. “He’s saying he’s willing to work to get things done, which is a fairly decent message given voters’ frustration with Congress.”

Tennessee values statesmen. A lot of political experts, and Tennessee politicians themselves, point to the grandfather of the modern GOP in Tennessee, the late statesman and Senate majority leader, Howard Baker Jr. The diplomat, senator, and chief of staff to Ronald Reagan was knownin Washington as “the great conciliator.”

If you look at the Republican politicians who have come in his wake, they put pragmatism over ideological purity, including Tennessee’s other GOP senator, Bob Corker, a businessman and former mayor of Chattanooga. In April, the GOP state legislature approved one of Republican Gov. Bill Haslam’s biggest priorities – free community college starting in the fall of 2015.

“This is Howard Baker’s state,” says Kyle Kondik of the University of Virginia Center for Politics. “They’re not fire-and-brimstone Republicans.” Carr, however, says the state’s changing, and that’s why Alexander made sure his campaign machinery was well-oiled.

Alexander focused early on campaign machinery. Like other establishment senators who beat tea party opponents this year – Mitch McConnell of Kentucky and Lindsey Graham of South Carolina, to name two – Alexander locked in his endorsements early and made sure he had plenty of money in the bank.

He most of the Tennessee GOP congressional delegation to back him, which limited the number of high-profile Republicans in the state who could challenge him. That left a state representative (Carr) and a Memphis radio station owner (George Flinn). Alexander has outspent Carr 5 to 1, according to reports of campaign-finance disclosures.

When it comes to opponents, the more the merrier. Besides Carr and Mr. Flinn, four other Republicans are challenging Alexander on Thursday, which makes his Republican opposition more diffuse. Alexander also doesn't need to top 50 percent to win the primary. Ms. Duffy thinks that only two of Alexander’s opponents can crack single digits “and the rest will be lucky to get 1 percent.” The point is that “if there is an anti-Alexander vote out there, they have lots of options.”

Know your state. Kansas Republican Sen. Pat Roberts was pilloried by his tea party opponent for being AWOL from his state. Though Senator Roberts survived his primary this week, the vote was closer than expected. But that charge can’t stick against the Tennessee senator. After losing his first bid for governor, Alexander, in 1978, traded in his campaign suit for a red-and-black plaid shirt and hiking boots, and started on a 1,000 mile walking tour across Tennessee to get to know voters. It worked, and he won. (He also broke out his signature plaid shirt for his two presidential runs but did not win.)

In his two terms in the Senate, he has spent more than half his nights in Tennessee, according to an Alexander aide. The senator just finished a bus tour of more than 40 stops.

“People who get in trouble in electoral politics usually take someone for granted," Alexander told Dan Balz at The Washington Post. "I think every time you run for election you start from the bottom and work your way back up again. That's what I'm trying to do."